litmus-rt.git/drivers/cpufreq, branch linux-tip

[CPUFREQ] add sampling_down_factor tunable to improve ondemand performance

2010-10-22T15:44:47+00:00

Adds a new global tunable, sampling_down_factor.  Set to 1 it makes no
changes from existing behavior, but set to greater than 1 (e.g. 100)
it acts as a multiplier for the scheduling interval for reevaluating
load when the CPU is at its top speed due to high load.  This improves
performance by reducing the overhead of load evaluation and helping
the CPU stay at its top speed when truly busy, rather than shifting
back and forth in speed.  This tunable has no effect on behavior at
lower speeds/lower CPU loads.

This patch is against 2.6.36-rc6.

This patch should help solve kernel bug 19672 "ondemand is slow".

Signed-off-by: David Niemi 
Acked-by: Venkatesh Pallipadi 
CC: Daniel Hollocher 
CC: 
CC: 
Signed-off-by: Dave Jones

[CPUFREQ] drivers/cpufreq: Adjust confusing if indentation

2010-10-22T15:44:47+00:00

Indent the body of for_each_cpu.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// 
@r disable braces4@
position p1,p2;
statement S1,S2;
@@

(
if (...) { ... }
|
if (...) S1@p1 S2@p2
)

@script:python@
p1 << r.p1;
p2 << r.p2;
@@

if (p1[0].column == p2[0].column):
  cocci.print_main("branch",p1)
  cocci.print_secs("after",p2)
// 

Signed-off-by: Julia Lawall 
Signed-off-by: Dave Jones

[CPUFREQ] fix brace coding style issue.

2010-08-03T17:47:05+00:00

This patch fixes up a brace warning found by the checkpatch.pl tool

Signed-off-by: Neal Buckendahl 
Signed-off-by: Dave Jones

[CPUFREQ] x86 cpufreq: Make trace_power_frequency cpufreq driver independent

2010-08-03T17:47:05+00:00

and fix the broken case if a core's frequency depends on others.

trace_power_frequency was only implemented in a rather ungeneric way
in acpi-cpufreq driver's target() function only.
-> Move the call to trace_power_frequency to
   cpufreq.c:cpufreq_notify_transition() where CPUFREQ_POSTCHANGE
   notifier is triggered.
   This will support power frequency tracing by all cpufreq drivers

trace_power_frequency did not trace frequency changes correctly when
the userspace governor was used or when CPU cores' frequency depend
on each other.
-> Moving this into the CPUFREQ_POSTCHANGE notifier and pass the cpu
   which gets switched automatically fixes this.

Robert Schoene provided some important fixes on top of my initial
quick shot version which are integrated in this patch:
- Forgot some changes in power_end trace (TP_printk/variable names)
- Variable dummy in power_end must now be cpu_id
- Use static 64 bit variable instead of unsigned int for cpu_id

Signed-off-by: Thomas Renninger 
CC: davej@redhat.com
CC: arjan@infradead.org
CC: linux-kernel@vger.kernel.org
CC: robert.schoene@tu-dresden.de
Tested-by: robert.schoene@tu-dresden.de
Signed-off-by: Dave Jones

[CPUFREQ] ondemand: don't synchronize sample rate unless multiple cpus present

2010-08-03T17:47:04+00:00

For UP systems this is not required, and results in a more consistent
sample interval.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Jocelyn Falempe 
Signed-off-by: Mike Chan 
Signed-off-by: Andrew Morton 
Signed-off-by: Dave Jones

[CPUFREQ] unexport (un)lock_policy_rwsem* functions

2010-08-03T17:47:04+00:00

lock_policy_rwsem_* and unlock_policy_rwsem_* functions are scheduled
to be unexported when 2.6.33. Now there are no other callers of them
out of cpufreq.c, unexport them and make them static.

Signed-off-by: WANG Cong 
Cc: Venkatesh Pallipadi 
Signed-off-by: Dave Jones

[CPUFREQ] ondemand: Refactor frequency increase code

2010-08-03T17:47:04+00:00

Make simpler to read and call.

*** v3 - Always call when powersave_bias is enabled.

Acked-by: Venkatesh Pallipadi 
Signed-off-by: Mike Chan 
Signed-off-by: Dave Jones

[CPUFREQ] fix memory leak in cpufreq_add_dev

2010-08-03T17:47:02+00:00

We didn't free policy->related_cpus in error path err_unlock_policy.
This is catched by following kmemleak report:

unreferenced object 0xffff88022a0b96d0 (size 512):
  comm "modprobe", pid 886, jiffies 4294689177 (age 780.694s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [] create_object+0x186/0x281
    [] kmemleak_alloc+0x60/0xa7
    [] kmem_cache_alloc_node_notrace+0x120/0x142
    [] alloc_cpumask_var_node+0x2c/0xd7
    [] alloc_cpumask_var+0x11/0x13
    [] zalloc_cpumask_var+0xf/0x11
    [] cpufreq_add_dev+0x11f/0x547
    [] sysdev_driver_register+0xc2/0x11d
    [] cpufreq_register_driver+0xcb/0x1b8
    [] 0xffffffffa032e040
    [] do_one_initcall+0x5e/0x15c
    [] sys_init_module+0xa6/0x1e6
    [] system_call_fastpath+0x16/0x1b
    [] 0xffffffffffffffff

Signed-off-by: Xiaotian Feng 
Cc: Thomas Renninger 
Cc: Prarit Bhargava 
Signed-off-by: Dave Jones

[CPUFREQ] revert "[CPUFREQ] remove rwsem lock from CPUFREQ_GOV_STOP call (second call site)"

2010-08-03T17:47:01+00:00

395913d0b1db37092ea3d9d69b832183b1dd84c5 ("[CPUFREQ] remove rwsem lock
from CPUFREQ_GOV_STOP call (second call site)") is not needed, because
there is no rwsem lock in cpufreq_ondemand and cpufreq_conservative
anymore.  Lock should not be released until the work done.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=1594

Signed-off-by: Andrej Gelenberg 
Cc: Mathieu Desnoyers 
Cc: Venkatesh Pallipadi 
Signed-off-by: Andrew Morton 
Acked-by: Mathieu Desnoyers 
Signed-off-by: Dave Jones

Merge branch 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2010-05-18T15:49:13+00:00

* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, hypervisor: add missing 
  Modify the VMware balloon driver for the new x86_hyper API
  x86, hypervisor: Export the x86_hyper* symbols
  x86: Clean up the hypervisor layer
  x86, HyperV: fix up the license to mshyperv.c
  x86: Detect running on a Microsoft HyperV system
  x86, cpu: Make APERF/MPERF a normal table-driven flag
  x86, k8: Fix build error when K8_NB is disabled
  x86, cacheinfo: Disable index in all four subcaches
  x86, cacheinfo: Make L3 cache info per node
  x86, cacheinfo: Reorganize AMD L3 cache structure
  x86, cacheinfo: Turn off L3 cache index disable feature in virtualized environments
  x86, cacheinfo: Unify AMD L3 cache index disable checking
  cpufreq: Unify sysfs attribute definition macros
  powernow-k8: Fix frequency reporting
  x86, cpufreq: Add APERF/MPERF support for AMD processors
  x86: Unify APERF/MPERF support
  powernow-k8: Add core performance boost support
  x86, cpu: Add AMD core boosting feature flag to /proc/cpuinfo

Fix up trivial conflicts in arch/x86/kernel/cpu/intel_cacheinfo.c and
drivers/cpufreq/cpufreq_ondemand.c